Umbilical cord blood (UCB) has been an alternative source for patients with hematologic diseases who may be potentially cured by allogeneic hematopoietic cell transplantation. In addition, UCB is an important stem cell source for other promising technologies, such as large-scale ex vivo productions of hematopoietic stem cell (HSC)-derived red blood cells and platelets. In the 25 years following the first successful case of transplantation in 1988, more than 30,000 UCB transplantations have been performed with > 600,000 UCB units stored worldwide. Initially, UCB transplantation was mainly performed in children, given the concern of low cell dose. As cell dose is critical for engraftment and survival, infusing two units of UCB has been a popular practice for adult patients. However, this approach makes HLA matching even more challenging. Remarkably, it has been estimated that current total UCB collections represent < 5% of potentially available cords. Therefore, there is an unmet need for innovative and low-cost solutions to increase the number and HLA diversity of banked UCB units, as well as to overcome the cell dose limitation of each UCB unit. Furthermore, an international survey conducted by the World Marrow Donor Association in 2013 revealed that nearly 90% of public UCB banks are not financially sustainable. Recently, we have developed an innovative microbubble- based technology for rare cell isolation in blood that can help resolve these issues. We use perfluorocarbon- filled microbubbles (MBs), which have been used as a safe ultrasound contrast agent, to create targeted agents for sorting. Therefore, this material would be suitable for isolating cells for therapeutic applications. We will create the targeted microbubble based system to isolate HSCs, which leads to substantial reduction of the final product volume (< 1 ml) compared to current standard unit (> 20 ml) for banking. This factor alone will lead to > 20-fold savings on long-term storage in liquid nitrogen. The simplicity of the procedure has been shown in publications, and reduction of the cost may revolutionize the UCB banking industry to facilitate realization of emerging innovations in cell based therapies, aside from more conventional hematopoietic cell transplantation. We have accomplished key feasibility milestones for the phase I grant and will develop a closed system to isolate HSCs from UCB for potential clinical applications, including hematopoietic transplantation and ex vivo blood production. Moreover, this system can also be conveniently adapted for HSC isolation from other sources, including peripheral blood and bone marrow.